The present invention relates to molecules which have structures and functions that mimic the gamma chain that is shared by several cytokine receptors. The present invention relates to the use of such molecules to modulate cytokine activity and cytokine mediated functions.
A family of related cytokine receptors including the receptors for IL-2, IL-4, IL-7, IL-9, IL-13 and IL-15 have been reported to share a common protein chain, the xcex3-chain, for maximal ligand induced receptor binding and signaling. The xcex3-chain is a member of the cytokine receptor superfamily which includes receptors for growth hormone, erythropoietin, IL-3, IL-2, IL-4, IL-7, IL-6 and GM-CSF. The xcex3-chain is a 64 kd protein with a fibronectin type II and CKR-SF domain which share structural homology.
The crystal structure of the human growth hormone receptor has been published by deVos A. M., et al. 1992 Science 255:306-312, which is incorporated herein by reference, and shows that the receptors form a homodimer to bind ligand and induce a signal. The receptors for IL-4 have been shown to be in the form of a heterodimer consisting of IL-4xcex1 and the common xcex3-chain. A model for the human IL-4:IL-4-Receptor interaction has been published by Gustchina, A. et al. 1995 PROTEINS: Structure, Function and Genetics 21:140-148, which is incorporated herein by reference.
Cytokine:receptor complexes are very important mediators of many immune responses. For example, T cell growth and differentiation is regulated in part by IL-2, IL-4, IL-7, IL-9, and IL-15. These cytokines have also been reported to play a role in other immunological functions as well.
Without the xcex3-chain, the cytokine receptors which normally form complexes with the xcex3-chain are much less efficient in binding their ligands and thus transmitting their signals to the target cells. Evidence for the central role of the xcex3-chain includes the findings that mutations in this receptor have been demonstrated to be the causative factor in the development of severe combined immunodeficiency. Recently, Boussiotis, V. A. et al. 1994 Science 266:1039-1047, which is incorporated herein by reference, demonstrated that the development of T cell anergy can be abrogated by signaling through this receptor by various means.
The function and activity of cells of the immune system are regulated and directed by cytokine:receptor interactions as is signaling which induces growth and proliferation. The activation of T cells and B cells is regulated by cytokine:receptor interactions including cytokine:receptor interactions involving receptors which include the xcex3-chain in a heterodimer.
There is a need for pharmaceutical compositions which can effectively inhibit the immune responses mediated by cytokine:receptor interactions. There is a need for a method of inhibiting cytokine mediated cell activation, function, growth and/or proliferation. There is a need for pharmaceutical compositions which can effectively inhibit signaling that involves receptors which include the xcex3-chain. There is a need for compositions and methods which can inhibit or suppress immune responses in order to therapeutically or prophylactically treat individuals who have conditions, diseases or disorders involving immune abnormal or undesirable immunological activity.
The present invention relates to peptide mimics of the loops on the xcex3-chain which either interact with cytokines or the partners of the xcex3-chain in heterodimeric cytokine receptors that include the xcex3-chain. The peptides of the present invention are based on human and murine xcex3-chain sequences. The sequences homology for the human and murine xcex3-chain is high (71% identical and 82% similar) making the translation from one species to the next more direct.
The peptide mimics bind to the cytokine or partner receptor and inhibit cytokine activity. Inhibitors of the common xcex3-chain inhibit the function of IL-2, IL-4, IL-7, IL-9, IL-13 and IL-15 by preventing their binding to their respective receptors. Thus, the inhibition of these cytokine mediated events leads to immuno-suppressive responses which are beneficial for the prevention or treatment of numerous auto-immune diseases and graft rejection following various types of transplant procedures as well as diseases associated with hyperproliferation of T cells and/or B cells. For example, many lymphomas are dependent on some of these cytokines (IL-2 for T cell lymphomas and IL-4 for B cell lymphomas) for growth.
The present invention relates to peptides that consist of 5 to 25 amino acids including: SEQ ID NO:1 IQLYQTF, SEQ ID NO:2 IHLYQTF, SEQ ID NO:3 CLQYLV, SEQ ID NO:4 CLEHLV, SEQ ID NO:5 CLQYLT, SEQ ID NO:6 CLEHLT, SEQ ID NO:7 CLQYLTQ, SEQ ID NO:8 CLEHLTQ, SEQ ID NO:9 PIAGSSQQ, SEQ ID NO:36 PICGSSQQ, SEQ ID NO:10 PLCGSAQH, SEQ ID NO:11 PLAGSAQH, SEQ ID NO:12 NHEPRFLS, SEQ ID NO:13 DYRHKFSL, SEQ ID NO:14 LNLQNL, SEQ ID NO:15 LKLQNL, SEQ ID NO:16 NLSESQL, SEQ ID NO:17 KLSEQL or such an amino acid sequence with one or more conservative substitutions, wherein the peptide inhibits cytokine mediated signal transduction.
The peptides of the invention preferably have constrained conformations and most preferably are cyclic. In preferred embodiments, cysteine residues are provided at the termini of the peptides to form di-sulfide bonds which result in the formation of cyclic peptides.
According to some embodiments of the present invention, peptides are selected from the group consisting of: SEQ ID NO:18 CIQLYQTFC, SEQ ID NO:19 CIHLYQTFC, SEQ ID NO:20 CLQYLVC, SEQ ID NO:21 CLEHLVC, SEQ ID NO:22 CLQYLTC, SEQ ID NO:23 CLEHLTC, SEQ ID NO:24 CLQYLTQC, SEQ ID NO:25 CLEHLTQC, SEQ ID NO:26 CPIAGSSQQC, SEQ ID NO:37 CPICGSSQQC, SEQ ID NO:27 CPLCGSAQHC, SEQ ID NO:28 CPLAGSAQHC, SEQ ID NO:29 CNHEPRFLSC, SEQ ID NO:30 CDYRHKFSLC, SEQ ID NO:31 CLNLQNLC, SEQ ID NO:32 CLKLQNLC, SEQ ID NO:33 CNLSESQLC, SEQ ID NO:34 CKLSESQLC and derivative peptides thereof. The derivative peptides consist of amino acid sequences which contain one or more conservative substitutions. Conservative substitutions include the following:
I may be substituted with V, A or L;
Q may be substituted with N;
L may be substituted with V, A or I;
Y may be substituted with F;
V may be substituted with I, A or L;
S may be substituted with T;
A may be substituted with V, I or L;
N may be substituted with Q;
E may be substituted with D;
F may be substituted with Y;
D may be substituted with E; and
I may be substituted with V, A or L.
In some preferred embodiments, the V in sequences SEQ ID NO:3 CLQYLV and SEQ ID NO:4 CLEHLV are substituted with T to improve solubility in aqueous solutions. Accordingly, peptides SEQ ID NO:22 CLQYLTC, SEQ ID NO:23 CLEHLTC, SEQ ID NO:24 CLQYLTQC and SEQ ID NO:25 CLEHLTQC are provided.
The peptides of the invention are derived from sequences of the murine or human cytokine receptor common gamma chain.
The peptides correspond to murine cytokine receptor gamma common chain residues SEQ ID NO:l IQLYQTF (100-106), SEQ ID NO:3 CLQYLV (161-166), PICGSSQQ (207-214), SEQ ID NO:12 NHEPRFLS (181-188), SEQ ID NO:14 LNLQNL (124-129), SEQ ID NO:16 NLSESQL (142-148) and the corresponding sequences from the human cytokine receptor gamma common chain, i.e. SEQ ID NO: 2 IHLYQTF, SEQ ID NO:4 CLEHLV, SEQ ID NO:11 PLAGSAQH, SEQ ID NO:13 DYRHKFSL, SEQ ID NO:15 LKLQNL and SEQ ID NO:17 KLSEQL.
The peptides SEQ ID NO:18 CIQLYQTFC, SEQ ID NO:19 CIHLYQTFC, SEQ ID NO:20 CLQYLVC, SEQ ID NO:21 CLEHLVC, SEQ ID NO:26 CPIAGSSQQC, SEQ ID NO:37 CPICGSSQQC, SEQ ID NO:27 CPLCGSAQHC, SEQ ID NO:28 CPLAGSAQHC, SEQ ID NO:29 CNHEPRFLSC, SEQ ID NO:30 CDYRHKFSLC, SEQ ID NO:31 CLNLQNLC and SEQ ID NO:32 CLKLQNLC are modeled to mimic the regions of the cytokine receptor gamma common chain predicted to interact with ligands and the peptides SEQ ID NO:33 CNLSESQLC and SEQ ID NO:34 CKLSESQLC are modeled to mimic the regions of the cytokine receptor gamma common chain predicted to interact with other cytokine receptor chains with which the gamma chain forms heterodimers as an active receptor complex.
According to the invention, the peptides of the invention inhibit cytokine mediated signaling that involves cytokine receptors which include the gamma chain. Cytokines IL-2, IL-4, IL-7, IL-9, IL-13 and IL-15 each interact with receptor complexes that include the gamma chain. Accordingly, the peptides of the invention can be used to inhibit IL-2, IL-4; IL-7, IL-9, IL-13 and IL-15 signaling. Through this inhibition, the peptides of the invention are useful to suppress immunological responses and functions. For example, these cytokines are involved in immunological activity in which cells are induced to grow, proliferate and/or release factors, cytokines or other molecules including antibodies. The peptides of the invention can be used to inhibit these activities.
Inhibition of T cell and/or B cell proliferation is useful in the treatment of many diseases and conditions including, but not limited to, leukemia, lymphoma, graft versus host disease and other transplant rejections, allergies, asthma and autoimmune and inflammatory diseases such as rheumatoid arthritis, lupus, multiple sclerosis and myasthenia gravis. The peptides of the invention can also inhibit the growth of B cells and T cells and/or inhibit T cells and B cells from releasing substances. Thus, by inhibiting cell growth and/or proliferation and/or function of cells involved in the immune system, the peptides can be useful to suppress the immune system.
The present invention relates to methods of preventing and treating diseases involving or mediated by cells of the immune system. According to some embodiments of the invention, patients are administered compounds of the invention in an amount sufficient to suppress immune function sufficiently to have a therapeutic effect on patients suffering from such diseases involving undesirable function, activity, growth or proliferation of cells of the immune system. According to some embodiments of the invention, patients are administered compounds of the invention in an amount sufficient to suppress immune function sufficiently to have a preventive effect on patients at risk of developing diseases, disorders or conditions involving undesirable function, activity, growth or proliferation of cells of the immune system.